Locating an object within a subterranean formation may be desirable. For example, it may be desirable to map a subterranean formation to locate buried pipes. Additionally, it may be desirable to locate other buried objects, for example, locating a human in a collapsed building or locating a human or object in a tunnel, cave, or other subterranean formation by mapping. Subterranean mapping techniques may include radio frequency (RF), ground penetrating radar (GPR), resistivity, micro-gravity, conductivity, electromagnetic, and magnetometry mapping techniques.
U.S. Pat. No. 6,097,189 to Arndt et al. discloses a system for locating an object disposed within a first medium having a conductivity and a permittivity may include one or more elements such as a transmitter for producing a transmit signal so that the transmit signal has at least one transmitter frequency. The transmitter may preferably be movable in a second medium adjacent to the first medium. A target antenna is provided for the object such that the target antenna produces a reradiated signal upon being radiated with the transmit signal. A first receiver is tuned to the reradiated signal frequency. A comparison unit may be used that has a memory element operative for storage of the indicia of conductivity. The comparison unit and the memory element have circuitry for comparing the transmit signal and the reradiated signal to determine a relative position between the transmitter and the target antenna using the indicia of conductivity.
Further improvements to mapping or tracking in a subterranean formation may be desirable. For example, it may be desirable to more quickly and easily map a subterranean object to more quickly repair a pipe, or locate a human, for example.